Control unit for hydraulic steel bending apparatus



y 1956 H. M. SHUFF 2,745,385

CONTROL UNIT FOR HYDRAULIC STEEL BENDING APPARATUS Filed April 23, 19522 Sheets-Sheet l INVENTOR.

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May 15, 1956 H. M. SHUFF 2,745,385

CONTROL UNIT FOR HYDRAULIC STEEL BENDING APPARATUS Filed April 23, 1952I 2 Sheets-Sheet 2 IN V EN TOR.

United States Patent O CONTROL UNIT FOR HYDRAULIC STEEL BENDINGAPPARATUS Horace M. Shulf, Brookmont, Md. Application April 23, 1952,Serial No. 283,793

1 Claim. (Cl. 121-45) The present invention relates in general tobending machines, and more particularly to an improved bending machinefor forming metal stock of various cross sections, such as metalreinforcing rods, to desired shapes without incurring wrinkling orbuckling of the metal at the location of the bend, together with meansfor accurately controlling the degree of bend of the stock.

Heretofore, metal bending machines have been common in which theworkpiece is bent to the desired shape by forming or wrapping the stockaround a die member. A particular bending machine of this type is thatdisclosed in my earlier patent, No. 2,460,951, granted February 8, 1949,in which the .bending die is carried by a rotary table. It is adifficult matter, however, to accurately and precisely control therotary movement of the turntable on which the die is mounted to thenecessary extent to produce bending of the stock to exact preselectedangles.

It is, therefore, an object of the present invention to provide animproved bending machine for producing bends in metallic rods orelongated stock, in which the bending of the stock can be carried outwith consistent accuracy and at a rapid rate.

Another object of the present invention is the provision of an improvedbending machine for elongated metal stock in which the stock can beeasily and rapidly inserted into and removed from the machine.

A further object of the present invention is to provide an improvedbending machine for elongated metal stock of the type in which presetmeans are provided to automatically and precisely control the degree ofbend imparted to the stock by the machine.

Another object of the present invention is the provision of an improvedbending machine for bending elongated metal stock of the type employinga rotary turntable and die in which preset means are provided toaccurately and precisely control the amount of rotation imparted to theturntable and die, to thereby accurately control the degree of bend ofthe stock.

Another object of the present invention is the provision of a novelmanually set control attachment for hydraulically powered rotary metalbending dies for automatically controlling the extent of rotation of thedie and the degree of bend of the metal stock.

Other objects, advantages and capabilities of the present invention willbecome apparent from the following detailed description taken inconjunction with the accompanying drawings wherein only a preferredembodiment of the invention is illustrated.

in the drawings:

Figure l is a top plan View of a metal bending machine embodying thepresent invention, with the control rod and hydraulic pump controllinglever intercoupled therewith shown in neutral position and the hydrauliccylinder rack and associated components stopped in a positionintermediate its limits of travel, parts being broken away for clarity;

Figure 2 is a vertical longitudinal section of the metal bending machinetaken along the lines 22 of Figure 1;

Figure 3 is a vertical transverse section through the turntable andassociated control components of the metal bending machine taken alongthe lines 3-3 of Figure 1;

Figure 4 is a top plan view of the metal bending machine illustratingthe position of the various components at the beginning of the bendingstroke of the machine;

Figure 5 is a top plan view of the metal bending machine illustratingthe components in their relative positions at the beginning of a returnstroke of the machine; and I V Figure 6 is a schematic view of thehydraulic power supply components for the machine, and particularlyillustrating the neutral seeking hydraulic control valve employed inconjunction therewith;

The invention in general involves the use of a hydraulic power systemfor imparting rotation to a turntable supporting a rotary die forbending elongated metal stock, such as a reinforcing rod. The systemincludes a pump and control valve for regulating flow of the hydraulicfluid to and from a hydraulic jack driving a rack and pinion coupled tothe turntable.

The invention is particularly concerned with the provision of anadjustable control unit arranged alongside the turntable and coupled tothe control valve. The control unit is provided with stop elementshaving energy storage means associated with each, in which energy isstored during movement of the rack before the rack reaches itspreselected limit of movement. The energy storage means and abutmentstops cooperate. with resilient catch means for holding the control rodin positions to establish forward or reverse flow of hydraulic fluidthrough the control valve so that when the control rod is set inposition to establish forward or reverse flow of hydraulic fiuid to thejack, the resilient catch means holds the rod in such position until arack arm engages the abutment stop. The resulting impact disables theresilient holding means and throws the control rod and control valve toneutral position. The adjustment of the position of the abutment stops,therefore, permits accurate automatic control of the rotary movement ofthe tumtable and the degree of bendimparted to the metal reinforcing rodby the rotary die.

The invention will be more fully understood from the following detaileddescription having reference to the drawings wherein like referencecharacters designate corresponding parts throughout the several figures.The metal bending machine of the present'invention is particularlysuitable for portable use, and to this end is designed to be mounted ona worktable, generally indicated by the reference character 19, whichmay be the platform of an automotive truck. The die mechanism forimparting the bend to the workpiece, such as the metal reinforcing rod,indicated by reference character 11, of the type used in reinforcedconcrete, is generally indicated at 12, and corn prises a turntable 13mounted for rotation about its center on the worktable it The turntablel is welded to a vertical shaft 14 for imparting rotation to theturntable and is provided with a downwardly extending cylindricalprojection 15 having a ball bearing race defined therein, forming a ballthrust bearing 16 with a bearing plate 17 rigidly secured as by bolts tothe worktable Ill. The shaft 14 extends through an accommodatingaperture 17' in the bearing plate 17 and is provided with a pinion gear18 keyed thereto as by an adjustable key and uideway 19 for impartingrotation to the die from means to be later described.

The rotary die, generally indicated at 20, is formed of a die sleeve 21adapted to be fitted over the upwardly projecting portion of the shaft14 extending above the furntablelial. Sleeves of varying diameters areto be.

titled with a circular aperture 23 adapted to fitover' the shaft 14, andis designed to lie flush" on'the' turntable on a radial axis thereof. Anaperture 24 is provided adjacent the outer end of the die arm 22designed to register with a complementary aperture 13 in the turntable13 to'receiv'e a locking pin 24 and maintain the die'arm 22' at a fixedradial'posifion on' the turntable 13.

Air upstanding shoulder or die pin 25' is formed on the die arm 22 withits inner end spaced from the outer periphery of thedie sleeve 21 theproper distance to just accommodate the reinforcing rod 11' of theparticular size desired to :be bent. The die arm 22 is designed to beinterchangeable so that die arms having die pins 25 spaced. variousdistances from the .center of the aperture 23" maybe interchangeablyemployed to accommodate different sizes of reinforcing rods.

An abutment guide isprovided on the Work table 10, as indicatedgenerally by the reference character 26, to hold the-reinforcing, rod orstock 11 against movement in the direction opposite the direction ofbend imparted the rotary die during the bending operation, but to permitsuch translatory or longitudinal movement of the stock as'may becausedby the bending action of the die arm 22 on the stock. This guide 26generally comprises a housing 27 which may, if preferred, be anchored inslots in the worktable to render the housing adjustable on anaxisparallel to that of the reinforcing rod 11. Within the housing isdisposed an adjustable abutment element 28 having a bearing roller 28-on the end thereof disposed adjacent the turntable 13 and having anadjustment'screw 28" on the other end thereof threaded throughthehousing 27. to permit manual adjustment of the position of thebearing roller 28'- relative to the reinforcing rodll.

The structure thus far described, with the exception of the specificball thrust bearing for the turntable l3 and the pinion gear I8 on theshaft 14, corresponds to the rotary'die mechanism and abutment guidedisclosed in myearlier Patent No. 2,460,901.

The means for rotating the pinion gear 18 to drive the turntable 13 androtary die arm 22 is derived from the truck power takeofl or othersuitable power takeoff, indicated generally by the reference character30, and is indicated generally in Figures 1 and 2. The power takeofi 30is coupled through a belt and pulley coupling indicated at 31 to aconventional integrated .power pack 32 This power pack, in accordancewith conventional practice, comprises a hydraulic pump, a reservoir, and

of each of the chambers 45 and 46 are coupled through suitable conduitsto. each of the hydraulic fluid conduits 33 and 34 coupling fluid toopposite ends of the hydraulic cylinder 35. p

The control valve 42 is of the neutral seeking or selfcentering type andto this end is provided with disc the control lever 48 pivoted to thevalve housing and biased as by means of springs 49 to dispose the valvediscs 45' and 46"i'n an intermediate position within their respectivechambers;blocking the input and; return conduits 43 and 44. When the.control. lever 48 is shifted laterally against the bias of the springs49 to the position marked forward, the valve discs 45' and 46 arepositioned to couple the input conduit 43 with the fluid conduit 34, andthe fluid conduit 33 with the return con-. duit 44, to pump fluid intothe left-hand end of the hydraulic cylinder 45' andforce the piston 36and rack 38 to the left as viewed inFig'ure 6. When the lever 48 isshifted to the reverse position, the valve discs 4-5 and 46- are shiftedto couple the input conduit 43 with fluid conduit 33 and fluid conduit34 with return conduit 44 to reverse direction 'of movement of thepiston 36 and therack 38. I

The control means for automatically controlling the degree of rotationof the rotary die mechanism 12 comprises essentially a control rod 50disposed longitudinally on the worktable 10 in parallel relation to therack 38 and piston rod: 37'. The control rod 50 is guided for slidingmovement along its axis by a spring catch and guide unit 51, andby 'alaterally projecting follower arm 38" integrally'forrned with the rack38 and having its end formed into an annular ring snuggly accommodatingthe rod 50. The inwardly disposed end of the rod table Itl'and controlvalve 42 to shift the control valve lever 48 between theforward' andreverse positions.

The spring catch and guide unit 51 is rigidly mounted on the work table10 and is provided with a tubular portion 5-3 accommodating the rod 50and upstanding portion 54 housinga spring biased ball55 which is adjustably tensionedby means of a suitable set screw. The

ahydrau'lic control valve, formed into an integrated unit,

to be driven from a suitable rotary power takeoff, such as available onconventional automotive trucks. The output of the power pack 32 iscoupled through hydraulic fluid conduits 3-3 and 34 to opposite ends ofa hydraulic jack or cylinder 35. A "piston 36 is' provided in thecylinder housing, a piston rod 37 projecting outwardly through one endof the cylinder 35. A rack 38 is integrally formed on the outer end ofthe piston rod 37, with the teeth of the rack held in engagement withthe teeth of the pinion gear 18, to drive the gear on linear movement ofthe piston 36, by means of a conventional roller hearing, such as isindicated at reference character 39 in Figures 1' and 3. 7 e

The hydraulic system for actuating the hydraulic jack and driving thepiston 36, piston rod 37 and rack 38 relative to the pinion 18', isschematically. illustrated in Figure 6. The integral power pack 32 iscomposed of a reservoir 40',- a hydraulic pump 41 and control valve 42.

Control valve 42 is provided with a supply and return conduit 43 and 44,respectively, coupled from the pump 41 and reservoir 49, respectively,to chambers 45 and 46 formed within the control valve body. The outletsspring biased ball 55 is adapted to cooperate with a pair of notches 56aand 565-. When the spring pressed ball 55 is fitted in thenotch 56a thecontrol rod 50 is held by the resilient locking action of the ball in aninwardly projecting position to hold the hydraulic valve control lever48 in forward position and pump hydraulic fluid through the conduit 34,forcing the rack 38 outwardly of the cylinder 35 and rotating theturntable '13 in a clockwise direction as viewed in Figures 1, 4 and 5,to impart a suitable bend to the reinforcing rod 11. This is theposition of the component's shown in Figure 4 when the notch 56!: is inregistry with the spring biased ball 55, and the rod 50 and bell crank52' are in their innermost position,-with the hydraulic valve controllever 48 held in forward position.

An adjustable abutment stop 57 forming the outer limit stop for thecontrol system is associated with the control rod 50 and comprises atubular sleeve 58 having a depending lug 58 housing an abutment screw 59which. is threaded therein and projects inwar ly of the inner end. ofthe annular sleeve .58.. A coil spring. 60 is suitably fixed to theinner end of the-sleeve 58 and projects beyond the end of the abutmentscrew ;59. A suitable spring biased pawl 61 is pivotallymountedon top ofthe sleeve 58 and is adapted to cooperate with a series of notches 62 onthe control rod 50, which are calibrated-in terms of degrees of rotationof the turntable 13 from zero position.

A similar reset limit stop 63 is provided inwardly of the limit stop 57and comprises a tubular sleeve 64 surrounding the rod 50 and fixedlypositioned thereon by means of a suitable set screw, the reset stop 63being provided with a threaded lug 64' housing through which is threadedan abutment screw 65 projecting forwardly of the inner end of the sleeve64. A coil spring 66 is likewise secured to the inner face of the sleeve64 and projects toward the stop 57 beyond the end of the abutment screw65.

The purpose of these two abutment stops 57 and 63 is to cooperate withthe arm 38 formed on the rack 38 to automatically limit the range ofmovement of the rack and the degree of rotation of the gear 18, andtherefore the degree of bend imparted to the reinforcing rod 11.Assuming that the follower arm 38, and the control rod 50 and lever 52are in the position illustrated in Figure 4, the hydraulic valve controllever 48 will be in the forward position to pump fluid to the cylinder35 and move the piston rod 37 and rack 38 outwardly of the cylinder,thus rotating the turntable 13 in a clockwise direction and moving thefollower arm 38' toward the limit stop 57. The rod 50 will be held inthe position shown in Figure 4 by the engagement of the resilientlybiased ball 55 and the detent 56a. It will be apparent from Figure 2that the annular ring of the follower 38' will engage the coil spring 60before it engages the abutment screw 59, thus compressing the coilspring 60 until the arm 38 engages the end of the abutment screw 59. Theshock of impact of the arm 38' with the abutment screw 59 will disengagethe notch 56a of the rod 50 from the spring biased ball 55, and theenergy stored up in the coil spring 60 will shift the rod 50 and bellcrank 52 to dispose the valve control lever 48 in neutral position,assisted by the springs 49 normally biasing the lever 48 to such neutralposition.

The control rod 50 may then be pulled toward the left, as illustrated inFigure 5, to shift the valve control lever 48 to reverse position andreturn the rack 38 and turntable 13 to Zero position shown in Figure 4.The turntable 13 and arm 22 are returned precisely to zero or startingposition during this reverse movement of the rack 38 by the reset limitstop 63 as the stop 63 effects disengagement of the notch 56b from thespring pressed ball 55 and returns the lever 48 to neutral in the samemanner that the limit stop 57 returns the control lever to neutral.

In using this device to eflect bending of metal stock such as steelreinforcing rods and the like, the die sleeve 21 and die arm 22 ofappropriate size for the reinforcing rod and the radius of bend desiredare put in place on the turntable 13. With the turntable in zero orstarting position as illustrated in Figure 4, and the spring biased pawl61 set in the appropriate notch 62 for the degree of bend desired, forexample 90, the control rod 50, which is assumed to be in neutralposition as in Figure 1, is then forced to the right as illustrated inFigure 2, shifting the hydraulic valve control lever 48 to forwardposition, pumping fluid to the hydraulic cylinder 35 and driving therack 38 outwardly of the cylinder 35 to rotate the turntable 13 and diearm 22.

The rod 50 is held in this position by seating of the spring pressedball 55 in the notch 56!: until the rack follower arm 38 engages theabutment screw 59 of limit stop 57. This impact upseats the ball 55 fromthe notch 56a to neutralize the system. At the time the follower arm 38'engages the abutment screw 59, the rack 38 will have moved the exactdistance necessary to rotate the turntable 13 and follower arm 22through a 90 arc from the zero position illustrated in Figure 4.

The rod 11 is then lifted out from between the die arm and sleeve 21 andthe control rod 50 is pulled to the left as illustrated in Figure 5, toshift the control Valve lever 48 to reverse and return the rack 38 andturntable 13 to zero position.

Abutment of the rack follower arm 38 with the screw 65 of reset stop 63unseats the spn'ng'pressed ball 65 from the notch 56!) and through thebell crank 52, returns the valve control lever 48 to neutral position.

It will be apparent from the foregoing description that a novel controlsystem for metal bending machines has been provided which may be presetfor desired degrees of bend of the metal stock and which precisely andrapidly bends the rods to the precise angle desired.

While but one specific embodiment of this invention has beenparticularly shown and described, it will be apparent that variousmodifications may be made therein within the spirit and scope of theinvention, and it is desired, therefore, that only such limitationsshall be placed thereon as are imposed by the prior art and are setforth in the appended claim.

What is claimed is:

A control unit for a hydraulic cylinder motor and piston actuated rackreciprocated thereby, and a control valve therefor having a neutralseeking control lever, said control unit comprising a manuallyadjustable rod for actuating said control valve to start and stop saidhydraulic cylinder motor and control the direction of movement of saidrack, means supporting said rod for reciprocal axial movement parallelto said rack, a pivoted bell crank lever intercoupling one end of saidrod with said neutral seeking control lever for positioning said controllever to terminate hydraulic supply to said motor and establish forwardand reverse flow supply thereto in accordance with displacement of saidrod, resiliently biased catch means cooperating with notches in said rodfor holding said rod in positions disposing said control lever in saidforward and reverse hydraulic supply positions, and means associatedwith said rod from a position supplying fluid to said motor to ahydraulic supply terminating position when said rack reachespredetermined outer and inner positions of travel, said lastnamed meansincluding a pair of abutment means supported in spaced relation on saidrod and an integral arm extending from said rack and having a collarthereon surrounding and slidable along said rod between said abutmentmeans, said abutment means each comprising an annular ring surroundingsaid rod having a stop element projecting therefrom to be engaged bysaid collar to shift said rod and decouple the same from said catchmeans and a coil spring projecting from said ring and beyond said stopelement to be compressed by said collar and store up energy immediatelyprior to contact of said collar with said stop elements and to releasethe stored up energy upon decoupling of said catch means from said rodto shift said rod and control lever to hydraulic supply terminatingposition, one of said abutment means being fixed on said rod to becontacted by said collar when said rack is at a preselected inwardlydrive-initiating position and the other of said abutment means beingadjustably positioned on said rod outwardly of said first abutment meansand adjacent the free end of said rod to be contacted by said collar ata selected point in its travel outwardly of said cylinder motor, saidrod having transverse notches adjacent the free end thereof graduated interms of degrees of movement of said rack, and said adjustablypositioned abutment means includes a pawl pivotally supported on theannular ring thereof and resiliently biased to dispose the nose of saidpawl into engagement with said transverse notches for resilientlyholding said adjustable abutment means at selected positions ofadjustment.

References Cited in the file of this patent UNITED STATES PATENTS346,190 Bryan July 27, 1886 (Other references on following page)

